U.S. and Turkish officials met on Friday to discuss impending American sanctions on Iran - an issue that has the potential to cause a new flashpoint in relations between the two NATO allies.

U.S. Assistant Secretary for Terrorist Financing Marshall Billingslea, who met with Turkish treasury and foreign ministry officials, said his talks in Ankara were very "positive" and that there was "no hostility" on either side. He also met with a series of Turkish companies.

Turkey's foreign ministry said for its part, that it was monitoring the sanctions and that authorities were working to ensure that Turkey is not "negatively impacted by the upcoming sanctions."

U.S. President Donald Trump announced in May that he would pull the United States out of a 2015 agreement over Iran's nuclear program and would re-impose sanctions on Tehran. His administration threatened countries with sanctions if they don't cut off Iranian oil imports by early November.

Turkey, which imports a more than half of its oil supplies from neighboring Iran, had earlier suggested that it did not intend to cut off trade with Iran, saying it was not obliged to abide by "unilateral" U.S. decisions.

U.S. Treasury officials have reportedly said in Washington that the U.S. may consider providing waivers from the sanctions to some countries which require time to cut oil imports from Iran.

Speaking to a small group of reporters in Ankara, Billingslea would not say, however, if Turkey would be granted exemptions.

"At this point, I'm not in a position to suggest that we are issuing waivers or exemptions," he said.

At the same time, Billingslea said that the U.S. was adamant about enforcing the new sanctions more "actively."

In May, a U.S. court convicted a Turkish banker from state-run Halkbank for his role in helping Iran evade U.S. economic sanctions. The key witness was Iranian-Turkish gold trader Reza Zarrab, who testified how he orchestrated the scheme and paid bribes to top Turkish officials. The bank said it was working closely with the U.S. Treasury Department and hoped not to incur damages, but the case has strained Turkish-American relations.

"This time around, the treasury sanctions will be enforced very, very aggressively and very comprehensibly," Billingslea said. "I think the Turkish government understands our position on that."

"We certainly would be very, very concerned about trying to trade with Iran in gold," Billingslea said, adding that the U.S. was tracking and trying to understand "large purchases of gold in Turkey."

Turkey, in its statement, said Iran was an "important neighbor" for "economic and commercial relations, as well as our energy imports."

According to data from the country's Energy Market Regulator, Turkey imported 3 million tons of crude oil from Iran in the first four months of 2018, making up 55 percent of crude supplies and 27 percent of its total energy imports.

Billingslea said: "Iran may be a neighbor of Turkey but they are not a friend or an ally."